Remove tear-off menu feature in turtledemo

[Wulian233]

#58092 (BPO 13884) removed tear-off menu in IDLE, but it's still there in the turtledemo window.

tearoff=0 will disable tear-off vertical menu (it's even Windows 8's close window x style😨)

Last, I adjusted the scroll bar for previewing py files to the right. The original left side didn't fit the usage👀

There is no mention of tearoff in the Python docs, it seem like an outdated feature (but it is enabled by default)🤔

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Screenshout

Before

After

Linked PRs

• gh-120633: Remove tear-off menu feature in turtledemo #120634
• [3.13] gh-120633: Move scrollbar and remove tear-off menus in turtledemo (GH-120634) #120725

[Wulian233]

CC: @terryjreedy

[terryjreedy]

I am not sure how our backcompatibility rule apply to turtledemo, so I did not backport, at least not yet.